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Solid State, Core/Shell Structured QDs: Re-Dispersible in Organic Solvents and Aqueous Solutions

Quantum dots (QD) currently draw intensive research for applications due to their unique size-dependent optical and electrical properties.  CdSe based QDs are the most extensively used materials because of a size-tunable emission wavelength which lies in the visible light region of 450-650 nm.

Generally, CdSe cores in water solution have low fluorescence quantum yields (QY) due to surface-related trap states. However, this problem can be solved by growing wide band gap semiconducting shells around the core, such as zinc sulfide (best shell material for CdSe cores).

A complete line of Core(CdSe or CdSSe)/Shell(ZnS) QD in solid form are available from Strem.  These products are sold as mixtures in organic solvents and water, despite the hydrophobic organic ligand coatings.  A suitable surface coating provides stability in aqueous solutions and functionalizes the QDs for further surface modification. The emission wavelengths of QDs range from 450 nm (blue) to 665 nm (red), resulting in high quantum yield (>50%) and have narrow full-width half-maximum (FWHM).

Organic Soluble Quantum Dots

Solid state CdSe/ZnS core/shell QDs are coated with octadecyl amine

Catalog #’s:  48-1618, 48-1620, 48-1622, 48-1624, 48-1614, 48-1616

• Emission Range: 520-630 nm
• Full Width at Half Maximum (FWHM): <25nm or <35nm
• Highly purified
• High emission quantum yield (>50%)
• Soluble and stable in most non-polar organic solvents such as chloroform, toluene and hexane
• Specifically designed as emitter for optoelectronics

Solid state CdSeS/ZnS core/shell QD coated with oleic acid

Catalog #’s:  48-1602, 48-1604, 48-1606, 48-1608, 48-1610, 48-1612

• Emission Range: 450-665 nm
• Full Width at Half Maximum (FWHM): < 35 nm
• Highly purified
• High emission quantum yield (>50%)
• Soluble and stable in most non-polar organic solvents such as chloroform, toluene and hexane
• Specifically designed as emitter for optoelectronics

Water Soluble QDs

CdSSe/ZnS or CdSe/ZnS structured quantum dots with amine groups

Catalog #’s:  48-1644, 48-1646, 48-1648, 48-1650, 48-1652, 48-1654, 48-1656      

• Emission range: 400-665 nm
• polyethylene glycol (PEG) coating for less non-specific binding
• –NH₂ on the surface for easy reaction
• Full Width at Half Maximum (FWHM):  <25nm or 35 nm
• High emission quantum yield (>50%)
• Autoclavable
• Stable in most buffers in the pH range of 5-10 and cell medium with or without serum

Solid CdSSe/ZnS, CdS/ZnS or CdSe/ZnS structured quantum dots coating with carboxylic acid

Catalog #’s:  48-1630, 48-1632, 48-1634, 48-1636, 48-1638, 48-1640, 48-1642        

• Emission range: 400-665 nm
• Autoclavable
• Reactive group is a carboxylic acid
• FWHM <25nm or <35 nm
• High emission quantum yield (>50%)
• Stable in most buffers in the pH range of 5-10 and cell medium with or without serum

For more information on these products, please visit our website:

CdS, CdSe, CdSSe Solid Quantum Dots and Functionalized Quantum Dots in water